Frustrated with incorrect ICD10 codes used

I have an approved chronic condition and go for blood tests every 3-6 months. the same bloods, from the same lab. My last 2 claims were not submitted with the correct ICD10 code. I have spoken to people from lancet, I have emailed and asked that it be submitted with the correct code. I have contacted discovery and this still has not been resolved. Why do i pay medical aid if my approved chronic blood checks are not being covered? Why can Lancet not submit the claim with the correct ICD10 code, especially when I do these tests often? It is very frustrating, can someone please understand this problem and resolve it. I understand there might be a shortfall that I would have to pay, and that i understand, but not for the approved tests!